Battle of Rosenovo

The Battle of Rosenovo was a battle fought on the Romanian front of World War I in 1916. An Austro-Bulgarian division of eight regiments attacked a Russian division defending the disputed Dobrudja region (present-day Dobrich Province, Bulgaria) of Romania, which Bulgaria claimed as its own territory, and defeated the Russians after a hard-fought battle. Rosenovo was a rare instance of a Central Powers army consisting almost entirely of Bulgarian forces, with the Austro-Hungarian Army playing a sideshow role in the battle and the Imperial German Army having no presence whatsoever; in addition, despite the battle being fought on then-Romanian soil, no Romanian units were involved in the battle; rather, large numbers of Latvians and cossacks from the Baltics and southern Russia suffered heavy losses while fighting over foreign soil.

Background
Bulgaria had lost Dobrudja to Romania as part of the peace treaty which ended the Second Balkan War in 1913, but this humiliation fuelled Bulgarian revanchism in the following years. In 1915, Bulgaria entered World War I on the side of the Central Powers with the goal of reconquering lost territories, and Romania's entry into the war on the Entente side the following year justified a Bulgarian invasion. Bulgarian commander-in-chief Radko Dimitriev prepared an eight-regiment offensive against the Dobrudja region in 1916, with brigades from the 1st Sofiyski Infantry Regiment, the 36th Kozloduyski Infantry Regiment (two brigades), the 16th Lovchanski Infantry Regiment (two brigades), the 25th Dragomanski Infantry Regiment, and the 47th Infantry Regiment launching the offensive in conjunction with an Austro-Hungarian regiment. They faced three Imperial Russian Army frontnik regiments, three Latvian rifle regiments, and two cossack regiments.

Battle
The offensive started off poorly for the Central Powers. While Bulgarian riflemen picked off droves of Russian soldiers as they streamed down the hillsides, the Russians held off several Bulgarian attacks as they occupied the commanding hill on the battlefield and several artillery positions. The first phase of the battle saw the Bulgarians launch costly and demoralizing assaults on the Russian positions, but the Bulgarians eventually managed to secure a supply station to the south and a foothold in the north, flanking the Russian-held hill fortifications and turning the tide of the battle. The rest of the battle would be a back-and-forth battle for control of the hill and of the positions on its north and south slopes, with the supply station changing hands several times. The Bulgarians clearly held the upper hand at one point, only to lose the supply station to the Russians, who then gained the upper hand; the balance shifted once again as the Bulgarians reoccupied the supply station and the hill fortifications. Wave after wave of Russian cossacks and Latvian riflemen charged downhill to assault the Bulgarian foothold on the north slope of the hill, and Bulgarian reinforcements from the woodland artillery outpost surged in to retake the strongpoint each time it was overwhelmed. Later in the day, the Bulgarians achieved a breakthrough on all fronts, advancing from the foothold to the battered hillside which the Cossacks had been using as a staging point for their assaults. With the Bulgarians advancing full-force, the Russians were forced to withdraw, abandoning Rosenovo to the Central Powers and granting Bulgaria a proud, if costly, victory.